I have seen a lot of market acceptance for Litecoin and I think there will be adoption of "coins" out of the top five marketcap principally. My vps merchant now accepts about a dozen coins but none of them are graphene based coins. Steem may be the rational decision to make, but the market decides more on network effect than anything else.
Steem is even worse to privacy than bitcoin. You do not have to analyse the chain. It is all there on the blockchain. All of our transactions are tied to some identity.
If all of Bitcoin's transactions were put on Steem's we wouldn't even feel it.
Graphene in fact works wonders and I am a big fan of the technology.
For the privacy part.. might want to use services like CashShuffle for Bitcoin Cash or a privacy coin.